package com.easymin.weixin.service.impl;

import com.easymin.weixin.common.weixinSecure.AesException;
import com.easymin.weixin.common.weixinSecure.WXBizMsgCrypt;
import com.easymin.weixin.service.WeixinSecureCheckerService;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * @author zhyu
 * @date 2019-07-11 17:17:31
 */
@Service
public class WeixinSecureCheckerServiceImpl implements WeixinSecureCheckerService {

    @Value("${weixin.publicNumber.token}")
    private String token;
//    @Override
//    public boolean check(String encodingAesKey, String appId) throws AesException {
////        WXBizMsgCrypt pc = new WXBizMsgCrypt(token, encodingAesKey, appId);
////        assertEquals(afterAesEncrypt, pc.encrypt(randomStr, replyMsg));
////        return false;
//        return checkSignature();
//    }

    /**
     * 验证签名
     *
     * @param signature
     * @param timestamp
     * @param nonce
     * @return
     */
    public  boolean checkSignature(String signature, String timestamp,
                                         String nonce) {
        String[] arr = new String[] { token, timestamp, nonce };
        // 将token、timestamp、nonce三个参数进行字典序排序
        //Arrays.sort(arr);
        sort(arr);
        StringBuilder content = new StringBuilder();
        for (int i = 0; i < arr.length; i++) {
            content.append(arr[i]);
        }
        MessageDigest md = null;
        String tmpStr = null;

        try {
            md = MessageDigest.getInstance("SHA-1");
            // 将三个参数字符串拼接成一个字符串进行sha1加密
            byte[] digest = md.digest(content.toString().getBytes());
            tmpStr = byteToStr(digest);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        content = null;
        // 将sha1加密后的字符串可与signature对比，标识该请求来源于微信
        return tmpStr != null ? tmpStr.equals(signature.toUpperCase()) : false;
    }
    /**
     * 将字节数组转换为十六进制字符串
     *
     * @param byteArray
     * @return
     */
    private static String byteToStr(byte[] byteArray) {
        String strDigest = "";
        for (int i = 0; i < byteArray.length; i++) {
            strDigest += byteToHexStr(byteArray[i]);
        }
        return strDigest;
    }

    /**
     * 将字节转换为十六进制字符串
     *
     * @param mByte
     * @return
     */
    private static String byteToHexStr(byte mByte) {
        char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A',
                'B', 'C', 'D', 'E', 'F' };
        char[] tempArr = new char[2];
        tempArr[0] = Digit[(mByte >>> 4) & 0X0F];
        tempArr[1] = Digit[mByte & 0X0F];

        String s = new String(tempArr);
        return s;
    }

    public static void sort(String a[]) {
        for (int i = 0; i < a.length - 1; i++) {
            for (int j = i + 1; j < a.length; j++) {
                if (a[j].compareTo(a[i]) < 0) {
                    String temp = a[i];
                    a[i] = a[j];
                    a[j] = temp;
                }
            }
        }
    }
}
